1. Field of the Invention
This invention relates to timing systems for automatic watering or sprinkling apparatus and has particular reference to timing systems for automatically controlling a plurality of watering devices in a predetermined sequence and for predetermined lengths of time.
2. Description of the Prior Art
Watering systems of the above type have been in use for a number of years. However, such systems in general are controlled by electromechanical timing devices, as disclosed, for example, in the U.S. Pat. Nos. to Gustav A. Link, Nos. 3,000,398; 3,234,446; 3,780,766; 3,911,955; and 3,925,683. Although such prior systems are generally satisfactory, they are expensive to manufacture and tend to become unreliable since the mechanical elements are subject to wear and consequent malfunctioning after a period of time.